Study On Multi-floor Facility Layout Problem Based On M/g/1 Lift Handling System

On the condition of the fierce market competition that how to plan and design a reasonable, efficient layout for the multi-floor facilities is very important and urgent for the companies. And how to allocate lifts to handle the materiel is a key issue of the multi-floor facility layout problem .Using the queuing theory the paper anylize the lift allocation problem .And then it studys on the multi-floor facility layout problem (MFFLP) based on the analysis.Firstly, it makes a description of MFFLP and makes the material handling costs of multi-floor facility divided into two parts: the material handling cost between the departments on the same floor and the material handling cost between the departments on the different floors. At the same time it makes sure lift allocation problem is the key issue which affects the total material handling cost.Secondly it makes a description of lift allocation problem which is how to arrange the flows of the departments on different floor. Then it sets up the lift handling system by using M/G/1 queuing theory to get the formulas for calculating the running efficiency utilization, waiting time and stay time which are the key factors affect the cost of using vertical instrument. Then it presents the mathematical model of lift allocation problem. With the optimization result of the lift allocation problem as the cost between the departments on the different floors, it constitutes the cost model of MFFLP through quadratic set covering model., The cost model minimizes the material handling cost for the target and considers the floor limit, and also the conditions that the same department can't be separated to cross different floors.Thirdly it puts forward a one stage algorithm based on GA and SA for solving M/G/1 -MFFLP model, combined with the space-filling curve for layout of different area departments.It describes the key steps of the algorithm and given the process of the algorithm.Finally, it verificates the M/G/1 -MFFLP model with a case.It programs the algorithm on the platform of MATLAB and through comparing with the NL-MFFLP model based on nearest lift algorithm it verifies the M/G/1-MFFLP model is effective for sovling the MFFLP.